Simultaneous assessment of cerebral hemodynamics and contrast agent uptake in lesions with disrupted blood– brain–barrier

Heiland, Sabine; Benner, Thomas; Debus, Jürgen; Rempp, Katrin; Reith, Wolfgang; Sartor, Klaus

doi:10.1016/s0730-725x(98)00149-0

Cited by 57 publications

(48 citation statements)

References 21 publications

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“…ADC maps were generated on a pixel-by-pixel basis using the equation ADC = −ln (S 0 /S 1 )/(b 1 -b 0 ), where S 0 and S 1 are the signals of the two DWI that represent the average of 3 orthogonal planes, and b 0 and b 1 =0 and 1200 s/mm 2 , respectively. For PWI analysis, the method to calculate rCBF was adapted and modified from previous report (Heiland et al, 1999). as a change in relaxation rate was calculated using the equation: , where Si(t) is the signal intensity at the time point t, and S 0 is the averaged signal intensity at the time point before injection.…”

Section: Mri Data Analysismentioning

confidence: 99%

Efficacy of recombinant annexin 2 for fibrinolytic therapy in a rat embolic stroke model: A magnetic resonance imaging study

et al. 2007

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Efficacy of recombinant annexin 2 (rAN II) in a rat model of embolic stroke was examined using a magnetic resonance imaging (MRI) and histology. The right middle cerebral artery of male Wistar rats was occluded by autologous clots under anesthesia. Four doses of rAN II (0.125, 0.25, 0.5 and 1.0 mg/kg, n = 10 for each group) or saline (1 ml/kg, n = 10) were administrated intravenously within 5 min before clot infusion. Serial changes in apparent diffusion coefficient (ADC) and relative blood flow (CBF) were measured with the use of MRI in half of the animals in each group. The remaining half of the animals in each group was evaluated for hemorrhage and final infarct size by histology at 48 h after embolization. At 3 h after embolization, lesion volumes with ADC were abnormality and CBF in the peripheral lesion was improved in groups treated with 0.25, 0.5 and 1.0 mg/kg, but not 0.125 mg/kg, of rAN II in comparison with the saline-treated group (P < 0.05). Histological analyses were consistent with MRI findings. More importantly, no hemorrhagic transformation was documented in rats treated with 0.125 and 0.25 mg/kg of rAN II, whereas it was observed at higher doses. We concluded that rAN II at 0.25 mg/kg significantly reduced infarct size and improved CBF without hemorrhagic complications. rAN II is a novel compound that has the potential to be a promising fibrinolytic agent to treat embolic stroke.

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Section: Mri Data Analysismentioning

confidence: 99%

Efficacy of recombinant annexin 2 for fibrinolytic therapy in a rat embolic stroke model: A magnetic resonance imaging study

et al. 2007

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“…However, the relationship between the SI and the concentration of contrast agent (CA) is not linear 9 . To assess the exact hemodynamics of the tumor characterization by means of pharmacokinetics analysis, inversed T 1 (R 1 ) values that are linearly proportional to the concentration of CA must be calculated 10 .…”

Section: Introductionmentioning

confidence: 99%

Hemodynamic analysis of bladder tumors using T1-dynamic contrast-enhanced fast spin-echo MRI

Kanazawa

Miyati

Sato

2012

European Journal of Radiology

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Objectives: To evaluate the hemodynamics of bladder tumors, we developed a method to calculate change in R 1 value (∆R 1 ) from T 1 -dynamic contrast-enhanced fast spin-echo magnetic resonance imaging (T 1 DCE-FSE-MRI). Materials and Methods:On a 1.5-T MR system, T 1 DCE-FSE-MRI was performed. This study was applied to 12 patients with urinary bladder tumor, i.e. urothelial carcinoma. We compared R 1 -and SI-time between a peak in the R 1 -and SI-time curve occurred during the first pass within 60 s. Next, we assessed the slope of increase for 180 s after CA injection (Slope 0-180 ). Results:The mean slope of the first pass was significantly higher for bladder tumors on both the ∆R 1 -and the ∆SI-time curve compared with normal bladder walls. Moreover, a significant difference was apparent between bladder tumors and normal bladder walls on the mean Slope 0-180 in the ∆R 1 -time curve. However, no significant difference in the mean Slope 0-180 was observed on the ∆SI-time curve between bladder tumors and normal bladder walls. Conclusion: T 1 DCE-FSE-MRI offers three advantages: quantitative analysis;high-quality (i.e., artifact-free) images; and high temporal resolution even for SE 3 images. Use of ∆R 1 analysis with T 1 DCE-FSE-MRI allows more detailed information on the hemodynamics of bladder tumors to be obtained and assists in differentiation between bladder tumors and the normal bladder wall.

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“…Others process data only from regions that do not demonstrate contrast enhancement (15). Some use small-flipangle gradient-echo (GRE) (6,19,20) or dual-echo (21) acquisitions to minimize the T1 leakage effects. Alternatively, a loading dose of contrast agent may be administered prior to acquiring the dynamic susceptibility-weighted contrastenhanced data to minimize subsequent changes in T1 that might occur during the first-pass dynamic susceptibility-weighted contrast-enhanced study (9,22).…”

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confidence: 99%

Comparison of Dynamic Susceptibility-weighted Contrast-enhanced MR Methods: Recommendations for Measuring Relative Cerebral Blood Volume in Brain Tumors

Paulson¹,

Schmainda²

2008

Radiology

301

347

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Purpose:To investigate whether estimates of relative cerebral blood volume (rCBV) in brain tumors, obtained by using dynamic susceptibility-weighted contrast material-enhanced magnetic resonance (MR) imaging vary with choice of data acquisition and postprocessing methods. Materials and Methods:Four acquisition methods were used to collect data in 22 highgrade glioma patients, with informed written consent under HIPAA-compliant guidelines approved by the institutional review board. During bolus administration of a standard single dose of gadolinium-based contrast agent (0.1 mmol per kilogram of body weight), one of three acquisition methods was used: gradient-echo (GRE) echo-planar imaging (echo time [TE], 30 msec; flip angle, 90°; n ϭ 10), small-flip-angle GRE echo-planar imaging (TE, 54 msec; flip angle, 35°; n ϭ 7), or dual-echo GRE spiral-out imaging (TE, 3.3 and 30 msec; flip angle, 72°; n ϭ 5). Next, GRE echo-planar imaging (TE, 30 msec; flip angle, 90°; n ϭ 22) was used to collect data during administration of a second dose of contrast agent (0.2 mmol/ kg). Subsequently, six methods of analysis were used to calculate rCBV. Mean rCBV values from whole tumor, tumor hot spots, and contralateral brain were normalized to mean rCBV in normal-appearing white matter. Results:Friedman two-way analysis of variance and Kruskal-Wallis oneway analysis of variance results indicated that qualitative rCBV values were dependent on acquisition and postprocessing methods for both tumor and contralateral brain. By using the nonparametric Mann-Whitney test, a consistently positive (greater than zero) tumor-contralateral brain rCBV ratio resulted when either the preload-postprocessing correction approach or dualecho acquisition approach (P Ͻ .008 for both methods) was used. Conclusion:The dependence of tumor rCBV on the choice of acquisition and postprocessing methods is caused by their varying sensitivities to T1 and T2 and/or T2* leakage effects. The preloadcorrection approach and dual-echo acquisition approach are the most robust choices for the evaluation of brain tumors when the possibility of contrast agent extravasation exists. RSNA, 2008 Note: This copy is for your personal, non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, use the Radiology Reprints form at the end of this article. In 1990, Rosen et al (1) demonstrated that if a bolus of a gadolinium-chelated contrast agent is administered and images of the brain are acquired during this administration, a transient decrease in signal intensity occurs. This approach is based on the principle of susceptibilityweighted contrast material-enhanced magnetic resonance (MR) imaging, for which a bolus of a gadolinium-chelated contrast agent that is confined to the vasculature induces a difference in susceptibility between the vessel and the tissue. This signal intensity decrease can be converted into a concentration-time curve (⌬R2*[t]), from which cerebral blood volume can be computed for each image voxel, resulting...

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Simultaneous assessment of cerebral hemodynamics and contrast agent uptake in lesions with disrupted blood– brain–barrier

Cited by 57 publications

References 21 publications

Efficacy of recombinant annexin 2 for fibrinolytic therapy in a rat embolic stroke model: A magnetic resonance imaging study

Efficacy of recombinant annexin 2 for fibrinolytic therapy in a rat embolic stroke model: A magnetic resonance imaging study

Hemodynamic analysis of bladder tumors using T1-dynamic contrast-enhanced fast spin-echo MRI

Comparison of Dynamic Susceptibility-weighted Contrast-enhanced MR Methods: Recommendations for Measuring Relative Cerebral Blood Volume in Brain Tumors

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